CFC DNA Analysis & Interpretation 3

Question 1

Mitochondrial DNA (mtDNA) is particularly useful in forensic cases involving which type of evidence?

Accepted Answer

Hair shafts without roots, bones, and teeth

Answer

mtDNA is found in high copy numbers per cell, making it ideal for analyzing highly degraded or low-template samples like rootless hairs and ancient bones.

Question 2

The Combined DNA Index System (CODIS) database uses which core set of STR loci for forensic DNA profiling in the United States?

Accepted Answer

13 core loci established in 1997, expanded to 20 core loci in 2017

Answer

CODIS originally used 13 core STR loci; the FBI expanded the core to 20 loci effective January 2017 to reduce adventitious hits and increase discriminating power.

Question 3

In interpreting a DNA mixture, a forensic analyst determines that a suspect cannot be excluded. What additional information is essential to include in the report?

Accepted Answer

A statistical weight such as combined probability of inclusion or likelihood ratio

Answer

A cannot-exclude conclusion alone is insufficient; a statistical weight must accompany it to convey the significance of the non-exclusion.

Question 4

Which type of DNA testing is most appropriate for determining the maternal lineage of skeletal remains when nuclear DNA is too degraded?

Accepted Answer

Mitochondrial DNA HVI/HVII sequencing

Answer

Mitochondrial DNA is maternally inherited and present in high copy numbers, making mtDNA sequencing ideal for degraded samples and maternal lineage tracing.

Question 5

A DNA profile from evidence shows alleles at 18 of 20 CODIS loci matching a suspect. The two missing loci show no data. How should the examiner interpret this?

Accepted Answer

The profile is a match with a partial profile; statistical weight must reflect the tested loci only

Answer

Comparisons are valid for tested loci, but statistics must be calculated only on loci with results, and the partial nature must be disclosed.

(CFC) Certified Forensic Consultant Practice Test

(CFC) Certified Forensic Consultant Practice Test

CFC DNA Analysis & Interpretation 3